Fiber lasers for particle acceleration technologies

SOUTHAMPTON, England – A novel laser system combining the output of thousands of pulsed fiber lasers could be the solution to two main issues affecting current laser particle acceleration technologies: efficiency and repetition rates.

Scientists from the Optoelectronics Research Centre (ORC) at the University of Southampton have teamed up with three laboratories – École Polytechnique of Paris, the Fraunhofer Institute for Applied Optics and Precision Engineering, and CERN – to investigate the use of fiber lasers in groundbreaking particle accelerator technologies, such as the Large Hadron Collider – the world’s largest and highest-energy particle accelerator.

A new European Union-funded project, the International Coherent Amplification Network (ICAN), now aims to harness the efficiency, controllability and high average power capability of fiber lasers to produce high-energy, high-repetition-rate pulse sources. The international project, which will last 18 months, will develop a novel laser system combining the output of thousands of pulsed fiber lasers to achieve this feat.

Scientists from the Optoelectronics Research Centre (ORC) at the University of Southampton have teamed up with three international laboratories to investigate the use of fiber lasers in groundbreaking particle accelerator technologies, such as the Large Hadron Collider (LHC) – the world’s largest and highest-energy particle accelerator. Seen here, a view of the LHC machine taken on Nov. 20, 2009.
“High-energy ultrafast lasers have already been demonstrated, but the challenge to produce high-energy ultrafast pulses at high rates is a specialty for the ORC,” said Dr. Bill Brocklesby, project manager of ICAN. “Our track record in the development and fabrication of new optical fibers is unparalleled.”

Laser particle acceleration is a new and potentially revolutionary technology, but current lasers consume too much power and, to produce acceleration, can produce the required ultrafast laser pulses only around once per second. For many applications needing high repetition rates – x-ray and gamma ray generation, and particle acceleration – this makes the use of lasers economically unacceptable and prevents important scientific and societal laser applications in medicine, energy, environment, science and materials science from being implemented.

Fiber lasers, however, may resolve this issue. They not only operate at high average powers but also manage the heat generated by laser action. This enables them to produce pulses many thousands of times per second, and to accelerate particles at the high repetition rates necessary for real-world applications. In addition, fibers should also improve the overall power efficiency of suitable lasers by a factor of 1000, making them more economically feasible for experiments.

These fibers do have a drawback: Ultrafast fiber lasers can produce only lower-energy pulses because of optical nonlinearities in the fiber medium, meaning they don’t meet the requirements for high-energy physics.